From: Miaoqing Pan <miaoqing@xxxxxxxxxxxxxx> [ Upstream commit 8ed31a264065ae92058ce54aa3cc8da8d81dc6d7 ] If the interface type is P2P_DEVICE or NAN, read the file of '/sys/kernel/debug/ieee80211/phyx/netdev:wlanx/aqm' will get a NULL pointer dereference. As for those interface type, the pointer sdata->vif.txq is NULL. Unable to handle kernel NULL pointer dereference at virtual address 00000011 CPU: 1 PID: 30936 Comm: cat Not tainted 4.14.104 #1 task: ffffffc0337e4880 task.stack: ffffff800cd20000 PC is at ieee80211_if_fmt_aqm+0x34/0xa0 [mac80211] LR is at ieee80211_if_fmt_aqm+0x34/0xa0 [mac80211] [...] Process cat (pid: 30936, stack limit = 0xffffff800cd20000) [...] [<ffffff8000b7cd00>] ieee80211_if_fmt_aqm+0x34/0xa0 [mac80211] [<ffffff8000b7c414>] ieee80211_if_read+0x60/0xbc [mac80211] [<ffffff8000b7ccc4>] ieee80211_if_read_aqm+0x28/0x30 [mac80211] [<ffffff80082eff94>] full_proxy_read+0x2c/0x48 [<ffffff80081eef00>] __vfs_read+0x2c/0xd4 [<ffffff80081ef084>] vfs_read+0x8c/0x108 [<ffffff80081ef494>] SyS_read+0x40/0x7c Signed-off-by: Miaoqing Pan <miaoqing@xxxxxxxxxxxxxx> Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> Link: https://lore.kernel.org/r/1569549796-8223-1-git-send-email-miaoqing@xxxxxxxxxxxxxx [trim useless data from commit message] Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/mac80211/debugfs_netdev.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c index b1438fd4d8760..64b544ae9966b 100644 --- a/net/mac80211/debugfs_netdev.c +++ b/net/mac80211/debugfs_netdev.c @@ -487,9 +487,14 @@ static ssize_t ieee80211_if_fmt_aqm( const struct ieee80211_sub_if_data *sdata, char *buf, int buflen) { struct ieee80211_local *local = sdata->local; - struct txq_info *txqi = to_txq_info(sdata->vif.txq); + struct txq_info *txqi; int len; + if (!sdata->vif.txq) + return 0; + + txqi = to_txq_info(sdata->vif.txq); + spin_lock_bh(&local->fq.lock); rcu_read_lock(); @@ -658,7 +663,9 @@ static void add_common_files(struct ieee80211_sub_if_data *sdata) DEBUGFS_ADD(rc_rateidx_vht_mcs_mask_5ghz); DEBUGFS_ADD(hw_queues); - if (sdata->local->ops->wake_tx_queue) + if (sdata->local->ops->wake_tx_queue && + sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE && + sdata->vif.type != NL80211_IFTYPE_NAN) DEBUGFS_ADD(aqm); } -- 2.20.1
